Conventional cleaners for cleaning ground include brooms, mops and floor wipers, all of which are manual tools. With the development of science and technology, people pose high requirements for cleaners, and vacuum cleaner is developed, which operates to adsorb waste and dust on the ground through negative pressure produced by electric power. However, due to the limitation of the working principle, the vacuum cleaner fails to eliminate the waste and stains firmly attached to the ground. As a result, a new generation of cleaners for cleaning ground is provided. The new generation of cleaners includes a motor and a cleaning roller which is driven by the motor to clean the ground. The cleaning roller is often made of sponge. The cleaning capability of the cleaners is proportional to the thickness of the sponge roller, the thicker the sponge roller, the stronger the cleaning capability. The new generation of cleaners is also equipped with a water supply system and a water channel for washing the cleaning roller, thus cleaning the ground completely.
After being washed, water in the sponge roller is required to be squeezed out using a squeezing structure, or the water tends to flow to the ground when the sponge roller is squeezed on the ground. On the one hand, the action force the squeezing structure exerts on the sponge roller is favorable to the removal of the water, on the other hand, the action force is resistant to the rolling of the sponge roller. That is to say, for a thick sponge roller, when the squeezing force is too small, the water cannot be removed, when the squeezing force is too large, the resistance to the sponge roller is large, which causes the waste of the energy.